The BBC’s TV chief has ordered a sweeping internal investigation into Top Gear amid concerns about racism and offensive gaffes on the show.

The review of the show’s culture and practices, ordered by BBC director of television Danny Cohen, follows controversial presenter Jeremy Clarkson being given a final warning over his behaviour on the BBC2 programme.

It is understood that workers on the show were asked if they thought the programme was racist. The investigation also explored whether a culture existed where people were afraid to speak out when they found things offensive.

Clarkson, executive producer Andy Wilman as well as presenters James May and Richard Hammond were among the many interviewed as part of the report, it is understood.

TV bosses also want to address concerns about whether Clarkson and others are “aware of their responsibilities” and the conduct expected of them as BBC stars and employees.

The report has also explored whether there has been a damaging breakdown in the relationship between the show’s producers and BBC management, which had contributed to the problems.

Cohen is desperate to stem the tide of controversy which has engulfed the show in recent times, including two recent rows about racism.

Last week Ofcom found that Clarkson “deliberately” used offensive racial language in Top Gear’s Burma special.

Top Gear: Jeremy Clarkson said ‘there’s a slope on it’ when discussing a bridge in the Burma special. Photograph: BBC

The report, which has only been seen by Cohen and a small number of others, was ordered after Clarkson nearly lost his job in May after an outtake came to light which showed him using the N-word.

The review emerged as a compromise between Cohen and director general Tony Hall.

The internal report is understood to have borne out of these discussions and was tasked with looking at the culture that allows these gaffes to “slip through the net”.

As part of looking at the culture of the show, there were concerns that the N-word footage may have been leaked because of a fear of publicly objecting during the making of the Burma special.

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Jeremy Clarkson ‘begs forgiveness’ over N-word footage

There are also serious worries from bosses about whether Clarkson and others on the show recognise the conduct that is expected of them as BBC stars.

One particular case, where a photo was posted on Clarkson’s Twitter account showing him asleep with a sheet of paper held beside his head with an expletive written on it, caused particular concern to some at the BBC.

This has been one of a seemingly frequent tide of rows and complaints about the show.

In recent years this has included racism claims after he named his black dog Didier Dogba after the Chelsea striker.

There were 31,000 complaints after he joked that striking public sector workers should be “executed in front of their families”.

There was also a row about offensive comments made about Mexicans on the show.

It was known that Clarkson and former BBC2 controller Janice Hadlow enjoyed a particularly frosty relationship, particularly after she confronted him over comments he had made when she had attended a recording of the programme.

The report has been completed and returned to Cohen but its findings are being kept firmly under wraps. It is understood the dossier was not widely circulated and only went to Cohen and a few others.

After the report was handed in to the director of television there was a meeting between management and production bosses to talk about “things that were raised” in the report.

The investigation is thought to have gone on for four to six weeks and started in June.

The BBC would not reveal the findings of the report and refused to comment.

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